1. Field of the Invention
This invention relates to an apparatus for explosively dispersing particles of combustible metals into the atmosphere to form a fuel-air explosive. Also, this invention relates to a composition, which enhances the performance of metal augmented charge (MAC) devices.
2. Description of the Related Art
A conventional fuel-air explosive (FAE) device event consists of two stages. In the first stage, the liquid fuel is explosively dispersed to form a large fuel-air cloud. In stage two, a high explosive secondary charge is detonated to generate a shock wave, which initiates detonation of the dispersed medium.
These explosives comprise an air combustible hydrocarbon, such as propane, butane, ethylene oxide, gasoline, or the like, disposed in a suitable tank surrounding a central charge of high explosive. Detonation of this high explosive disperses the hydrocarbon throughout the environment. After a delay, which permits the formation of a vapor cloud, the fuel-air mixture is usually ignited by means of a secondary delayed charge.
While this type of explosive may be thought of as deriving a significant part of its energy from the environment, being based on the use of totally different materials, namely liquid hydrocarbons, there are significant limitations in the handling and application of such munitions. These relate to problems stemming from the use of liquids in tanks, which present special hazards relating to leakage, especially upon penetration, and generally the poor strength of tank structure. The explosive devices based on the present metallic reactive materials not only avoid such problems, but also offer many additional desirable features and capabilities, as discussed in detail below.
The mechanism of the MAC device includes an explosive dispersion charge in the charge system to disperse the fuel into the surrounding atmosphere. The primary detonation in this manner forms a cloud of atomized fuel and generates a strong primary air shock. The available atmospheric oxygen mixed with the cloud reacts instantly with the detonation products and generates the fuel-air explosive effect.
In recent years, single event FAE's have been developed. Single event FAE's disperse the fuel into a large cloud that detonates after a prescribed delay time. One version of an FAE is the turbulent jetting of a compatible chemical initiator, such as fluorine gas, into a dispersed cloud of fuel, such as hydrogen, creating a chemical reaction that results in self-detonation of the fuel cloud, as described in U.S. Pat. No. 5,168,123 issued to Lee on Dec. 1, 1992.
The metal liner of shaped charges is basically the source material for forming a hot metallic jet of immense penetration capability. The concave configuration of the explosive charge and the liner are both conducive to forming this hot metal jet. The mechanism of jet formation is basically a hydrodynamic phenomenon, operative in the liner material in bulk form. Self-forming-fragment (SFF) munitions are similar to shaped charge explosives, in the sense that the metal liner forms a mass of hot metal which is propelled in the direction of a target by the explosive charge, however with a lesser degree of jet formation. Nevertheless, as in the case of conventional shaped charges, the metal forms a relatively cohesive body of hot material propelled away from the point of detonation toward a target, but largely together, as a glob of material. Although these shaped charge type explosive devices may employ reactive metals, they do not derive a meaningful amount of energy from the interaction of the reactive metal with the environment, because the metal moves as a cohesive mass of material. While the degree of interaction with the environment may be greater for reactive metal of SFF type explosive devices, the directionality and concentration of the metal ejected from the explosive limits the amount of energy derived from any metal-air reaction.
By contrast, the present explosive propels and disperses combustible metal over a relatively large space surrounding the point of detonation in relatively finely divided form in order to enhance the metal surface area exposed to and reacting with the medium.
U.S. Pat. No. 5,852,256 issued to Hornig on Dec. 22, 1998 discloses a non-nuclear, non-focusing, active warhead that comprises a high explosive (HE) charge contained within a casing of reactive metal. In the '256 patent, a reactive metal reacts rapidly with the medium, such as air, in which the explosion takes place, or with a material which surrounds or is part of the target. However, the '256 patent describes this principle very broadly and does not provide formulations for the reactive metal. Further, the present invention provides formulations for a MAC that may be used in a similar manner, but with superior results to the '256 patent. The present invention uses flaked aluminum powder of specific sizes.